1. Field of the Invention
The present invention concerns an oral veterinary composition, containing the fluoroquinolone antimicrobial agent difloxacin or a pharmaceutically acceptable salt thereof. When administered orally to a ruminating animal (e.g., a cow or a feedlot calf), the present veterinary composition surprisingly provides (1) ready and extensive absorption of the fluoroquinolone from the rumen into the circulating blood and (2) an unexpectedly extended duration of therapeutic antimicrobial blood level.
2. Discussion of the Background
It is commonly believed that orally administered antimicrobials are not readily absorbed from the gastrointestinal tract of ruminating animals. Typically, the drug will be poorly absorbed, and will show blood levels of questionable therapeutic efficacy. Typically, the blood levels of an orally-administered antimicrobial are substantially lower than that of a dose administered parenterally. It is believed that fluoroquinolones are biodegraded in the rumen of adult ruminating animals, resulting in less active ingredient available for absorption.
The present Inventors have discovered that orally administered difloxacin is well-absorbed into a ruminant's blood and persists over a surprisingly long period of time, and at a level nearly equal the same dose of the drug administered parenterally. These are both unexpected and beneficial effects.